The small horns that stud the heads of many viper species may play a role in camouflage, suggesting they evolved as a result of the varying environments the snakes inhabit.
and at New York University Abu Dhabi in the United Arab Emirates studied whether horn evolution in these reptiles could be tied to environmental factors by analysing the physical features of 263 viper species to determine their evolutionary relationships to each other. They also compared horn placement â over the eyes or on the nose â with the vipersâ habitat preferences.
Eyebrow horns were associated with vipers that live in trees or open habitats, and nose horns were linked to those living on the forest floor. âThe common factor between arboreal habitats and rocky or sparsely vegetated habitats is a lack of cover,â says Busschau. Eyebrow horns âcould disrupt the outline of a viperâs head and possibly also conceal the eyes, allowing them to blend in better with their environmentâ, he says.
Advertisement
On forest floors, nose horns could make viper heads harder to spot among leaves and twigs.
The horns have independently evolved dozens of times in vipers across the world, suggesting that environmental pressures are pushing vipers to converge on the feature, the researchers argue.
at the University of Toronto in Canada wasnât too surprised by the findings. Forest habitats, particularly in the tropics, âprovide some of the most structurally diverse environments on Earthâ, he says. âComplex habitats provide a good opportunity for [visual camouflage] to evolve.â
Busschau says he plans to study the vipersâ genomes to find the DNA changes that underpin how the horns keep evolving.
Reference: bioRxiv, DOI:
Sign up for Wild Wild Life, a free monthly newsletter celebrating the diversity and science of animals, plants and Earthâs other weird and wonderful inhabitants
